The present invention relates to an internal combustion engine and a method of producing the internal combustion engine.
Conventionally, an internal combustion engine with a small size and a high output has been used in a carry-on type agricultural machine such as a pesticide spray machine and a lawn mower.
For example, Patent Reference has disclosed a conventional internal combustion small engine. In the conventional internal combustion small engine, a piston is disposed inside a cylinder chamber to be slide therein reciprocally in a vertical direction. The cylinder chamber includes a cylinder gas inlet and a cylinder gas outlet. The cylinder gas inlet is provided for sucking a mixture gas of a fuel and an air into the cylinder chamber. The cylinder gas outlet is provided for exhausting a combustion gas generated when the mixture gas is combusted in the cylinder chamber.
Patent Reference: Japanese Patent Publication No. 2005-233087
In the conventional internal combustion small engine disclosed in Patent Reference, the mixture gas is sucked at the same time the combustion gas is exhausted. Accordingly, the cylinder gas inlet temporarily becomes a communicated state with the cylinder gas outlet through the cylinder chamber. As a result, a part of the mixture gas sucked through the cylinder gas inlet may pass through the cylinder chamber, and may be directly exhausted through the cylinder gas outlet. When the mixture gas is sucked from the cylinder gas inlet and directly exhausted through the cylinder gas outlet, an output and fuel efficiency of the conventional internal combustion small engine tend to be lowered.
In view of the problems described above, an object of the present invention is to provide an internal combustion engine capably of solving the problems of the conventional internal combustion engine.
Further objects and advantages of the invention will be apparent from the following description of the invention.